Replacing your roof with a greener roof

While clay tile is on the expensive end of the roofing material spectrum, it is long-lasting and helps keep houses cool. (Photo: pdoyen/Flickr)

Time to replace your roof? Think about making decisions that will help out with energy, last longer and be lighter on the planet. First and foremost, your roof has to keep the water out of your house. When you’re reroofing, it’s a good time to add some extra insulation in your attic. If you’re installing roofing in Orlando or in another hot climate, you might consider a light color roof. Consider installing a more sustainable material than regular old fiberglass shingles, and take a look at solar panels, either integrated with the shingles or installed separately to generate some power for your house.

In terms of staying dry, any quality roofing material will do the job as long as it is installed correctly, with all the right flashing and sealants. Don’t rely on caulk to keep water out — everything must be properly lapped over the layer below to stay dry. Sidewall flashing must go under the felt paper or house wrap, chimney flashing must be counter flashed into the masonry, and where roofs stop at side walls, install kick out flashing to keep everything dry.

If, like most people, you have a vented attic, make sure you have enough ventilation at the eaves as well as at the ridge or gable ends. If you don’t have good eaves baffles to keep air from blowing through the attic insulation, have them installed, along with air sealing at the ceiling and adding loose fill fiberglass or cellulose on top of what is there. If you’re really ambitious, you could have a roofing contractor spray foam insulation on the roofline and close up all the vents, making your attic a semi-conditioned space.

Light color roofing can help keep your attic cooler, but don’t expect to see any big energy savings; they just aren’t there, especially if you have a really good layer of insulation on the ceiling or you have insulated the roofline. Light roofs will help cut down on the urban heat island effect where dark roofs and paving absorb heat during the middle of the day, then release it at the end of the day as it cools off. If everyone put on light color roofs, those hot summer nights might be a little cooler.

In terms of sustainable roofing materials, there are a lot of choices, unfortunately, most of them are more expensive than regular old fiberglass shingles. Depending on the slope of the roof, the climate and thickness, fiberglass shingles last between 20 and 40 years (not too shabby) but if you consider that a good home should last a hundred years or more, why not think about a roof that lasts as long as the house? I did a big renovation a while back on a 1918 house with an original clay tile roof. We took off all the tiles, stacked them up and reinstalled them, along with additional tiles that were reclaimed from another building. Although it was an expensive roof to install, the tiles had already lasted over 90 years and will easily last another 100 or more, maybe never needing replacement. On top of their durability, they help to keep the house cool because there is an air space between the tiles and the roof, and the broken ones were ground up and used for gravel under the driveway, keeping lots of waste out of the landfill. Some other sustainable roof materials are slate, concrete tile, metal and recycled rubber.

Finally, if you’re considering installing solar panels, and you live in a place where there are good incentives, when you reroof is the time to do it. There are solar panels available that can be nailed into the roof right along with the shingles, like PowerHouse from Dow. If you are installing a metal roof, you can get solar panels integrated right into the roof sections. Or, you can go with the old standby, regular panels that are attached to a rack system on the roof.

There are many opportunities to make your home more sustainable when replacing your roof. Whether it’s choosing energy efficient or sustainable materials, including more insulation, or adding solar power, or just making sure that everything is installed properly to keep the house dry, there is something at every price level to consider.